I really hope that there will be an adapter for the original NES... I purchased the Retrode2 just so I could play my old games, but I mistakenly thought that they were SNES. I was wrong I have *some* N64 games, but most of the cartridges that I have are NES.

Sorry to hear about your confusion about SNES/NES. I'm afraid my plans for an NES plug-in are pretty low on the priority list (like, page 3 or 4 in a 10pt font) so I can't make any promises there. One thing I can promise is that, should there ever be a NES plug-in, it will be nowhere nearly as much fun to use as the other cartridges, because for every game you put in you will have to make 4 or more settings by hand. NES cartridges were clearly not designed for easy dumping :-)

Just out of interest, would you do all that via retrode.cfg, or would you consider using switches on the unit itself? I would guess the latter would make it a lot less fiddly, though would of course bring the price up a little (and it would need either good labels or good documentation else it would be more confusing ).

There are currently two versions of NGP plug-ins supported in the firmware; my own (Sega slot) and ponrev's version (SNES slot). The file extension is hardcoded to .ngp since the config can be at most 1K

Little update re: the three adapters I've currently got in the pipeline (SMS, N64, GBx). Everything will be delayed a bit -- more Q3 or Q4 than Q2/2012, I'm afraid. On the other hand, the N64 one is VERY likely to get controller ports. The GBx will come with cartridge auto-detection (in earlier versions, you'd have to hit a reset button to trigger re-detection).